2007 GMC SIERRA check engine light

PASS-Key®III+ Operation
Your vehicle has PASS-Key®III+ (Personalized
Automotive Security System) theft-deterrent
system. PASS-Key
®III+ is a passive theft-deterrent
system. This means you do not have to do anything
special to arm or disarm the system. It works when
you transition the key to RUN, ACCESSORY or
START from the OFF position.
When the PASS-Key
®III+ system senses that
someone is using the wrong key, it prevents the
vehicle from starting. Anyone using a
trial-and-error method to start the vehicle will be
discouraged because of the high number of
electrical key codes.
If the engine does not start and the security light
on the instrument panel cluster comes on
when trying to start the vehicle, the key may have
a damaged transponder. Turn the ignition off
and try again.If the engine still does not start, and the key
appears to be undamaged, try another ignition
key. At this time, you may also want to check the
fuse, seeFuses and Circuit Breakers on
page 608. If the engine still does not start with the
other key, your vehicle needs service. If your
vehicle does start, the rst key may be faulty. See
your dealer who can service the PASS-Key
®III+
to have a new key made. In an emergency,
contact Roadside Assistance.
It is possible for the PASS-Key
®III+ decoder to
learn the transponder value of a new or
replacement key. Up to nine additional keys may
be programmed for the vehicle. The following
procedure is for programming additional keys only.
If all the currently programmed keys are lost or
do not operate, you must see your dealer or
a locksmith who can service PASS-Key
®III+ to
have keys made and programmed to the system.
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Warning Lights, Gages, and
Indicators
This part describes the warning lights and gages on
your vehicle. The pictures help to locate them.
Warning lights and gages can signal that something
is wrong before it becomes serious enough to
cause an expensive repair or replacement. Paying
attention to the warning lights and gages could also
save you or others from injury.
Warning lights come on when there may be or is a
problem with one of your vehicle’s functions. As
the details show on the next few pages, some
warning lights come on briey when you start the
engine just to let you know they are working. If
you are familiar with this section, you should
not be alarmed when this happens.Gages can indicate when there may be or is a
problem with one of your vehicle’s functions. Often
gages and warning lights work together to let
you know when there is a problem with your
vehicle.
When one of the warning lights comes on and
stays on as you are driving, or when one of
the gages shows there may be a problem, check
the section that tells you what to do about it.
Please follow this manual’s advice. Waiting to do
repairs can be costly and even dangerous. So
please get to know your vehicle’s warning
lights and gages. They can be a big help.
Your vehicle also has a Driver Information
Center (DIC) that works along with warning lights
and gages. SeeDIC Warnings and Messages
on page 279for more information.
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If, after several seconds, both status indicator
lights remain on, or if there are no lights at
all, there may be a problem with the lights or the
passenger sensing system. See your
dealer/retailer for service.
{CAUTION:
If the airbag readiness light in the
instrument panel cluster ever comes on
and stays on, it means that something may
be wrong with the airbag system. If this
ever happens, have the vehicle serviced
promptly, because an adult-size person
sitting in the right front passenger’s seat
may not have the protection of the
airbag(s). SeeAirbag Readiness Light on
page 250for more on this, including
important safety information.
Charging System Light
If this light comes on
when the engine is
running, there could be
a problem with the
charging system.
This light will also stay on while the key is in RUN
until the engine is started.
If the light stays on after starting the engine it
could indicate a problem with the generator drive
belt, or some other charging system problem.
Have it checked right away. Driving while this light
is on could drain the battery.
If you must drive a short distance with this light
on, it helps to turn off all of the electrical
accessories, such as the radio and the blower.
254

Malfunction Indicator Lamp
Check Engine Light
Your vehicle has a
computer which
monitors operation of the
fuel, ignition, and
emission control
systems.
This system is called OBD II (On-Board
Diagnostics-Second Generation) and is intended
to assure that emissions are at acceptable
levels for the life of the vehicle, helping to produce
a cleaner environment. The check engine light
comes on to indicate that there is a problem and
service is required. Malfunctions often will be
indicated by the system before any problem is
apparent. This may prevent more serious damage
to your vehicle. This system is also designed to
assist your service technician in correctly
diagnosing any malfunction.Notice:If you keep driving your vehicle with
this light on, after awhile, the emission controls
might not work as well, your vehicle’s fuel
economy might not be as good, and the engine
might not run as smoothly. This could lead
to costly repairs that might not be covered by
your warranty.
Notice:Modications made to the engine,
transmission, exhaust, intake, or fuel system
of your vehicle or the replacement of the
original tires with other than those of the same
Tire Performance Criteria (TPC) can affect
your vehicle’s emission controls and can cause
this light to come on. Modications to these
systems could lead to costly repairs not
covered by your warranty. This could also
result in a failure to pass a required Emission
Inspection/Maintenance test. SeeAccessories
and Modifications on page 486.
260

This light should come on, as a check to show
you it is working, when the ignition is on and the
engine is not running. If the light does not
come on, have it repaired. This light will also
come on during a malfunction in one of two ways:
Light Flashing— A misre condition has
been detected. A misre increases vehicle
emissions and may damage the emission
control system on your vehicle. Diagnosis and
service may be required.
Light On Steady— An emission control
system malfunction has been detected on your
vehicle. Diagnosis and service may be
required.
If the Light is Flashing
The following may prevent more serious damage
to your vehicle:
Reducing vehicle speed
Avoiding hard accelerations
Avoiding steep uphill grades
If you are towing a trailer, reduce the amount
of cargo being hauled as soon as it is
possibleIf the light stops ashing and remains on steady,
see “If the Light Is On Steady” following.
If the light continues to ash, when it is safe to do
so, stop the vehicle. Find a safe place to park
your vehicle. Turn the key off, wait at least
10 seconds and restart the engine. If the light
remains on steady, see “If the Light Is On Steady”
following. If the light is still ashing, follow the
previous steps, and see your dealer for service as
soon as possible.
If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully
install the cap. SeeFilling the Tank on page 493.
The diagnostic system can determine if the
fuel cap has been left off or improperly installed. A
loose or missing fuel cap will allow fuel to
evaporate into the atmosphere. A few driving trips
with the cap properly installed should turn the
light off.
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Did you just drive through a deep puddle
of water?
If so, your electrical system may be wet. The
condition will usually be corrected when the
electrical system dries out. A few driving trips
should turn the light off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel.
SeeGasoline Octane on page 489. Poor fuel
quality will cause your engine not to run as
efficiently as designed. You may notice this as
stalling after start-up, stalling when you put
the vehicle into gear, misring, hesitation on
acceleration, or stumbling on acceleration. (These
conditions may go away once the engine is
warmed up.) This will be detected by the system
and cause the light to turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at
least one full tank of the proper fuel to turn the
light off.
If none of the above steps have made the light
turn off, your dealer can check the vehicle.
Your dealer has the proper test equipment and
diagnostic tools to x any mechanical or electrical
problems that may have developed.Emissions Inspection and Maintenance
Programs
Some state/provincial and local governments have
or may begin programs to inspect the emission
control equipment on your vehicle. Failure to pass
this inspection could prevent you from getting a
vehicle registration.
Here are some things you need to know to help
your vehicle pass an inspection:
Your vehicle will not pass this inspection if the
check engine light is on or not working properly.
Your vehicle will not pass this inspection if
the OBD (on-board diagnostic) system determines
that critical emission control systems have not
been completely diagnosed by the system.
The vehicle would be considered not ready for
inspection. This can happen if you have recently
replaced your battery or if your battery has
run down. The diagnostic system is designed to
evaluate critical emission control systems
during normal driving. This may take several days
of routine driving. If you have done this and
your vehicle still does not pass the inspection for
lack of OBD system readiness, your dealer
can prepare the vehicle for inspection.
262

Oil Pressure Gage
Your vehicle may have an engine oil pressure
gage. It shows the engine oil pressure in psi
(pounds per square inch) when the engine is
running. Canadian vehicles indicate pressure in
kPa (kilopascals).
Oil pressure may vary with engine speed, outside
temperature and oil viscosity, but if readings
are outside the normal operating range, the oil
pressure light will come on. SeeOil Pressure Light
on page 264for more information.A reading outside the normal operating range may
be caused by a dangerously low oil level or
some other problem causing low oil pressure.
Check your oil as soon as possible. See
“OIL PRESSURE LOW” underDIC Warnings and
Messages on page 279andEngine Oil (Gasoline
Engine) on page 500.
{CAUTION:
Do not keep driving if the oil pressure is
low. If you do, your engine can become so
hot that it catches re. You or others could
be burned. Check your oil as soon as
possible and have your vehicle serviced.
Notice:Lack of proper engine oil maintenance
may damage the engine. The repairs would
not be covered by your warranty. Always follow
the maintenance schedule in this manual for
changing engine oil.United StatesCanada
263

Oil Pressure Light
This light will come on
briey when you start
your engine.
{CAUTION:
Do not keep driving if the oil pressure is
low. If you do, your engine can become so
hot that it catches re. You or others could
be burned. Check your oil as soon as
possible and have your vehicle serviced.Notice:Lack of proper engine oil maintenance
may damage the engine. The repairs would
not be covered by your warranty. Always follow
the maintenance schedule in this manual for
changing engine oil.
That is a check to be sure the light works. If it
does not come on, be sure to have it xed so it will
be there to warn you if something goes wrong.
When the light comes on and stays on, it means
that oil is not owing through your engine
properly. You could be low on oil and you might
have some other system problem.Security Light
This light ashes when
the vehicle security
system is activated.
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